Shrink _ASPendingState from 824 to 808 bytes, reduction of ~2% (Textu…

…reGroup#1483)

* Shrink _ASPendingState from 824 to 808 bytes, reduction of ~2%

These objects accumulate in the heap, so reducing their size will allow more to accumulate before memory warnings.

Shrink ASPendingState BOOLs. Use unsigned int for these bitfields for clarity. Separate from `_flags` as that struct is compared to `0` for testing. The `_boolFlags` struct is just storing other `BOOL`s.

* rename struct fields as suggested in garret's review.